The purpose of this study is to determine whether lack of suppression of glucagon causes hyperglycemia when insulin secretion is impaired but not when insulin secretion is intact. We started enrolling and studying healthy volunteers on February 26, 1998. Of the approved 24 healthy volunteers to be studied twice, up till now we have studied a total of 22 volunteers: three once, eighteen twice, and one twice. One volunteer has been disqualified because of nausea and another because of poor venous access. We would not need to go beyond the approved number of volunteers and the approved number of studies per volunteer to finish the study. We plan to continue studying the volunteers and finish the study by the end of 2000.